Limited evidenceBrain & cognition

Kola Nut

A West African seed chewed for alertness and once used to flavour cola drinks. Its stimulant effect comes from caffeine; there are essentially no modern trials of kola nut itself for cognition.

Evidence last reviewed: August 2026

What the science says

Alertness from caffeine Limited evidence
Kola nut contains roughly 1–3% caffeine along with theobromine, so any alerting effect is attributable to a known stimulant rather than to something unique to the seed. No controlled trial has measured attention or memory after kola nut in humans.
Cardiovascular effects Limited evidence
An early clinical observation study reported blood pressure and heart rate changes after kola nut ingestion, and a later clinical study in healthy volunteers examined kola nut's effect on cardiac repolarization alongside halofantrine. Both are small and focused on safety rather than benefit.

Dosage & safety

Studied doseTraditional use is 2–7 g of the fresh or dried nut chewed through the day, supplying roughly 40–200 mg of caffeine. Extract labels vary widely in caffeine content; no dose has been studied for cognitive benefit.

SafetyEffects are those of caffeine — insomnia, anxiety, palpitations, raised blood pressure — plus tannin-related stomach irritation and tooth staining. A clinical study raised the question of additive effects on cardiac repolarization when combined with QT-prolonging drugs, so avoid combining it with antimalarials, some antibiotics and antipsychotics without medical advice. Habitual chewing has been associated in observational research with oral and oesophageal cancer risk. Limit caffeine in pregnancy.

Scientific references

Comparative cardiac effects of antimalarial drug halofantrine with or without concomitant administration of kolanut or fluconazole in healthy volunteers
Adedapo AD, Ojji DB, Adedapo KS — Afr Health Sci, 2023
Some preliminary observations on the effects of kola nut on the cardiovascular system
Agatha M, Breckenridge C, Soyemi EA — Niger Med J, 1978

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